1. Field of the Invention
The present invention relates to a direction detection apparatus, a direction detection method, and a direction detection program, and also relates to a direction control apparatus, a direction control method, and a direction control program particularly suitable for use with an imaging apparatus to automatically track an object.
2. Description of the Related Art
When a video camera shoots speakers of a conference, attendees of a party, playing children, or the like without the intervention of a dedicated camera man or camera woman, since it is necessary to fix the video camera with a tripod or the like, the video camera shoots images only in one direction. Since images shot in this manner are unidirectional, they are often become monotonous because they are shot regardless of speakers and cheers in the situations.
To solve such a problem, techniques that automatically select an object and an angle of field, pan and tilt a camera corresponding to the selected object and angle of field, and cause the camera to track a noticeable direction without necessity of its operation have been proposed. Japanese Patent Application Laid-Open No. HEI 5-56426 describes a technique of preventing shooting directions from being unnecessarily changed and capable of recording natural and comfortable images.
In Japanese Patent Application Laid-Open No. HEI 5-56426, a speaker is detected with audio signals received from a plurality of microphones and a camera is controlled to shoot the detected speaker in close-up. In this method, after the speaker is detected, the detection operation is stopped for a predetermined period of time to prevent the camera from changing the shooting directions with input sounds such as noise and talking of other attendees (eg, a nod to a speech).
In this method, however, if the detection operation is set for a short stop time, the shooting directions of the camera are frequently changed. It is likely that recorded images would feel the audience uncomfortable. In particular, display apparatus that display recorded images are becoming large in recent years. Thus, if the shooting directions are frequently changed, images are rapidly moved. As a result, it is likely that the audience would feel very uncomfortable.
In contrast, if the detection operation is set for a long stop time to prevent such a problem, the camera is prevented unnecessarily from changing its shooting directions. Thus, in this method, it was difficult to set the detection operation for a proper stop time.